1. Field of the Invention
This invention relates to gear reducing devices and more particularly, to a combination chain and gear reducing device for application in sawmills and the like, which device is characterized by an input drive system and an output drive system located in a chamber or housing and separated by a rotating disc. The input drive system of the combination chain and gear reducing device includes an input shaft having one end rotatably seated in axial alignment in one end of an output shaft and extending from the housing and driven by an electric motor and belt combination. A spur and pinion gear is secured to or shaped integrally with the input shaft and engages a pair of oppositely-disposed, larger spur gears, each of which is provided with a fixed auxiliary spur gear, which spur gears and auxiliary spur gears ar rotatably mounted in spaced relationship on the disc. The auxiliary spur gears mesh with an output shaft spur gear that is keyed to the output shaft, which rotates independently of the input shaft, and, together with the spur gears, drive the disc. The auxiliary spur gears are rotatably mounted along with the spur gears, respectively, on a pair of spur gear shafts which are press-fitted in spaced relationship along a diameter of the rotating disc, which is rotatably mounted on the output shaft. Accordingly, rotation of the input shaft at a selected speed effects planetary rotation of the spur gears on the spur and pinion gear and the auxiliary spur gears on the output shaft spur gear. This rotation of the spur gears around the spur and pinion gear also effects rotation of the disc on the output shaft in the opposite direction from the direction of rotation of the input shaft.
The output drive system of the combination chain and gear reducing device includes an output shaft sprocket keyed to the output shaft, a fixed sprocket spaced from the output shaft sprocket and mounted in fixed relationship to the housing and a pair of double sprockets rotatably mounted on the disc in spaced relationship and along a diameter in ninety degree disposed relationship with respect to the auxiliary spur gears, respectively. A fixed sprocket leaf chain connects the fixed sprocket to a common set of teeth in the double sprockets and an output shaft sprocket leaf chain attaches the output shaft sprocket to an adjacent set of teeth in the double sprockets, respectively. Accordingly, rotation of the disc by operation of the input drive system effects rotation of the output shaft sprocket and the output shaft, since the output shaft sprocket is keyed to the output shaft. Rotation of the double sprockets drives the output shaft at a speed which is determined by the respective gear ratios of the spur and pinion gear, spur gears, auxiliary spur gears, output shaft spur gear, output shaft sprocket, fixed sprocket and double sprockets, respectively. The torque applied to the output shaft depends upon the relative number of teeth provided on the fixed sprocket and output shaft sprocket, respectively, located in the output drive system.
2. Description of the Prior Art
Various devices are known in the art for achieving a mechanical advantage in gearing, power transmission, speed reduction and the like. Early U.S. Pat. No. 846,086, dated Mar. 5, 1907, to G. E. Bouvier, et al, entitled "Gearing", details a differential driving connection for decreasing the speed of bobbins in a fly-frame as the bobbins are filled and increased in diameter, in order to assure that the yarn on the bobbin will be wrapped with a desired degree of tension. U.S. Pat. No. 2,140,790, dated Dec. 20, 1938, to I. R. Davis, is entitled "Power Transmission". The power transmission mechanism is designed to develop maximum power using a pair of bevel gears coupled to a system of spur gears. U.S. Pat. No. 2,210,598, dated Aug. 6, 1940, to R. K. Pepper, et al, details a "Power Clutch Unit" adapted for use in connection with heavy duty, slow speed mechanisms such as Caterpillar tractors, power-operated shovels, trucks and the like. U.S. Pat. No. 2,312,908, dated Mar. 2, 1943, to F. R. Ibanez, details a "Mechanism for Transmitting Power" which includes chain-connected sprockets and meshing gears for speed reduction purposes. "Variable-Speed Gearing" is detailed in U.S. Pat. No. 2,582,620, dated Jan. 15, 1952, to G. Colucci. The device includes one pair of variable diameter pulleys driven by a V-belt or chain where the tension is maintained in the chain or V-belt by the centrifugal force generated by rotation of the pulley system mounted on shafts carried by supports articulated to the axis of rotation of the pulley system. U.S. Pat. No. 2,653,490, dated Sept. 29, 1953, to E. Testori, details a "Progressive Variable Speed Drive Capable of Reverse Rotation". The system includes meshing gears and a V-belt and is designed to provide a progressive variable speed drive, by which it is possible to reach zero speed on the driven shaft while the driving shaft rotates at a selected speed. Reversal of the direction of rotation is also possible with the system. U.S. Pat. No. 3,130,608, dated Apr. 28, 1964, to L. H. Moran, details a "Chain-Type Speed Reducer" for transmitting power between rotatable members of the reducer and materially reducing the drive from a drive shaft to a driven shaft. The reducer employs a lever driven by the drive shaft for operating chains or the like circumferentially around a fixed sprocket to reduce the speed of the driven shaft. A "Variable Speed Power Transmission for Small Vehicles and The Like" is detailed in U.S. Pat. No. 4,048,871, dated Sept. 20, 1977, to N. G. Gyock. The transmission system includes primary and secondary transmissions connected in series, wherein a forward speed having a variable output depends upon the load placed on the input shaft to the primary transmission. The secondary transmission functions in one mode to reverse the direction of the output shaft, while the primary transmission operates to provide a variable gear ratio, depending upon the load placed upon the input shaft to the primary transmission.
It is an object of this invention to provide a combination chain and gear reducing device which utilizes an input shaft rotatably seated in one end of an output shaft, meshing gears engaging the input shaft and output shaft on the input side of a rotating disc, and chain-connected sprockets having a different number of teeth, connected to the output shaft on the opposite or output side of the disc, to create a mechanical advantage at the output shaft.
Another object of this invention is to provide a combination chain and gear reducing device which utilizes an input shaft rotatably and linearly terminating in an output shaft coupled to a system of gears located on the input side of a heavy disc or flywheel, to define an input drive system and sprockets connected by chains and having a different number of teeth and located on the opposite side of the flywheel to define an output system, for driving the output shaft at a selected speed and torque.
Yet another object of this invention is to provide a combination chain and gear reducing device which is characterized by an input drive mechanism having an input shaft carrying a spur and pinion gear that meshes with a pair of matching, oppositely-disposed spur gears and auxiliary spur gears which are, in turn, rotatably attached to a rotating disc and mesh with an output shaft spur gear keyed to an output shaft rotatably receiving the input shaft in axial alignment. The output drive mechanism includes a pair of spaced double sprockets rotatably mounted on the disc and connected by means of leaf, or silent chains to an output shaft sprocket having a first selected number of teeth and keyed to the output shaft and a fixed sprocket having a second selected number of teeth and secured to the housing of the combination chain and gear reducing device, respectively, for creating low speed, high torque operation of the output shaft.
A still further object of this invention is to provide a new and improved combination chain and gear reducing device which is characterized by a housing, an input shaft carrying a spur and pinion gear and journalled for rotation in one end of the housing and an output shaft journalled for rotation in the opposite end of the housing, one end of which input shaft is rotatably and axially seated in a corresponding end of the output shaft, and further including a disc or flywheel rotatably mounted on the output shaft and fitted with a pair of auxiliary spur gears for meshing with an output shaft spur gear keyed to the output shaft and a pair of spur gears meshing with the spur and pinion gear, for driving the disc at a speed proportional to the speed of the input shaft. The disc is further provided with a pair of double sprockets connected by means of leaf chains to an output shaft sprocket keyed to the output shaft and a fixed sprocket having a different number of teeth from the output shaft sprocket and located on the output side of the disc, to determine the output shaft torque.